feat: scaffold MySQL services with lifecycle and readiness checks

database/lifecycle_test.go

@@ -0,0 +1,39 @@
+package database
+
+import (
+	"context"
+	"database/sql"
+	"database/sql/driver"
+	"errors"
+	"sync/atomic"
+	"testing"
+)
+
+var failedPingClosed atomic.Int32
+var errPingUnavailable = errors.New("database unavailable")
+
+type failedPingDriver struct{}
+type failedPingConnection struct{}
+
+func (failedPingDriver) Open(string) (driver.Conn, error) { return failedPingConnection{}, nil }
+func (failedPingConnection) Prepare(string) (driver.Stmt, error) {
+	return nil, errors.New("not implemented")
+}
+func (failedPingConnection) Begin() (driver.Tx, error)  { return nil, errors.New("not implemented") }
+func (failedPingConnection) Close() error               { failedPingClosed.Add(1); return nil }
+func (failedPingConnection) Ping(context.Context) error { return errPingUnavailable }
+
+func init() { sql.Register("goOmniFailPing", failedPingDriver{}) }
+
+func TestOpenClosesPoolWhenStartupPingFails(t *testing.T) {
+	failedPingClosed.Store(0)
+	cfg := DefaultConfig()
+	cfg.Driver, cfg.DSN = "goOmniFailPing", "test"
+	pool, err := Open(context.Background(), cfg)
+	if pool != nil || !errors.Is(err, errPingUnavailable) {
+		t.Fatalf("unexpected startup result: db=%v err=%v", pool, err)
+	}
+	if closed := failedPingClosed.Load(); closed != 1 {
+		t.Fatalf("startup failure closed %d connections, want 1", closed)
+	}
+}